Subscriber identity modules, for example SIM (Subscriber Identity Module) cards, are usually produced in several steps.
ICCIDs (Integrated Circuit Card Identifiers) and IMSIs (International Mobile Subscriber Identities), which are also referred to as “resources” are first selected. Keys, for example authentication keys, PINS (Personal Identification Numbers), PUKs (Personal Unblocking Keys) and OTA (Over-the-Air) keys, are then generated.
The resources and keys, which are also referred to as “subscriptions”, are then created in back-end systems of a network operator, for example an HLR (Home Location Register), an accounting system and/or OTA (Over-the-Air) servers. The subscriber identity modules are then physically produced and shipped.
Since it takes a certain amount of time to create and in particular produce the subscriber identity modules, the steps described are normally carried out in batches typically comprising several hundreds to several thousands of subscriber identity modules. The batches produced are then directly shipped to wholesale customers or put in to storage. These are then typically delivered to end customers or points of sale from a warehouse in small numbers, for example between 1 and 100 items.
This storage is associated with several disadvantages. Firstly, it is costly, and secondly, the subscriber identity modules in question have to be destroyed or repaired with a great deal of complexity if the stored goods prove to be faulty or obsolete.
These disadvantages can be alleviated by the minimum storage time nmin being selected to be as short as possible. However, during production, it is not possible to just select nmin to be as short as you want for several reasons. Firstly, the physical production requires a certain amount of time, and secondly it takes a certain amount of time to create the subscriptions in the back-end systems.
Currently, communication profiles for eSIMs (embedded Subscriber Identity Modules) are also produced in the same way as the production of SIM cards described.